1. Field of the Invention
The invention relates in general to electrical transformers, and more specifically to new and improved methods of constructing transformers which include a cut, jointed amorphous metal core.
2. Description of the Prior Art
The core losses in the electrical transformers used by electric utility companies represents a significant loss of generated energy, even though transformers are highly efficient. With the increasing value of energy, ways of reducing these losses are constantly being sought. The use of amorphous metal in the magnetic cores of distribution and power transformers appears to be attractive, because, at equivalent inductions, the core losses of electrical grade amorphous metals are only 25% to 35% of the losses of conventional grain-oriented electrical steels.
Amorphous metals, however, in addition to their higher initial cost than conventional electrical steels, also pose many manufacturing problems not associated with conventional electrical steels. For example, amorphous metal is very thin, being only about 1 to 11/2 mils thick, and it is very brittle, especially after anneal. Amorphous metal is also very stress sensitive. Any pressure on the magnetic core, or change in its configuration after annealing, will increase its losses. Another characteristic of amorphous metal cores which creates manufacturing problems is the extreme flexibility of the core after it is wound. For example, a core wound of amorphous metal is not self-supporting. When the mandrel upon which the core is wound is removed, the core will collapse from its own weight, if the winding is not maintained in a vertical orientation.
The problems associated with amorphous metal cores have made the manufacture of the cores very labor intensive and very expensive. Various solutions to these problems have been proposed. See, for example, U.S. Pat. Nos. 4,592,133; 4,615,106; 4,723,349; 4,761,630; 4,766,407 and 4,709,471.
In spite of these disclosures, there remains a need for a method of manufacturing an amorphous metal core with reduced manufacturing cost and production line complexity.